This application proposes to continue studies of the involvement of intercellular communication via gap junctions and of cAMP mediated processes in hormone manipulated cell differentiation and function. The ovarian follicle and its component granulosa cells will be used for in vivo and in vitro studies the focus of which is to examine the subcellular kinetics of active cAMP dependent protein kinase. Tissues and cells at select stages of differentiation will be employed in order to test the possibility that their response, in terms of kinase activation, to steroid and/or protein hormones is altered as differentiation progresses. The ability of gap junctions to mediate the direct intercellular transfer of singals that cause dissociation of cAMP-dependent protein kinase will be further tested using cocultures of porcine ovarian granulosa cells and an adrenocortical tumor line (Y-1) or a transformed osteoblast line (MMB-1). Again, granulosa cells at select stages if differentiation will be used. Finally, attempts will be made to define biochemically the proteins of granulosa cells which bind the heat-stable inhibitor protein of cAMP-dependent protein kinase. Collectively, using cytochemical, morphological and biochemical procedures. These studies should better define the structural and chemical features that are involved in regulating the appropriate growth, differentiation and function of ovarian follicles and granulosa cells. Clkearly, a more thorough appreciation of mechanisms that influence cellular differentiation and function is needed in order to understand how aberrances of these processes may give rise to abnormal growth. Given that both gap junctional communication and cAMP-dependent processes have been thoroughly implicated as important constituents in the regulation of cell differentiation and function, the results of the studies proposed herein should add significant information to our knowledge of these events.